DE 10 2006 019 584 A1 reveals an electromagnetic pump designed as a reciprocating piston pump. A check valve is provided on the outlet side, with a valve body which is inserted fixedly between an outlet connection and a metering cylinder guiding a piston rod as well as an outlet flange. A disadvantage in this case is that impacts of the piston rod against the valve body cause noise and introduce vibration into the entire pump.
EP 1 748 188 A1 reveals an electromagnetic pump which is designed as a reciprocating piston pump and in which a check valve is provided on the outlet side. A valve body of the check valve is fixedly inserted in a metering cylinder interacting with a piston rod. In the event of contact between the piston rod and valve body, undesirable vibration and noise are produced, and these are only inadequately mitigated by a provided impact-damping surface.
DE 42 06 290 A1 reveals a solenoid-operated pump, the inlet side of which is sealed by a suction valve. The solenoid-operated pump comprises a magnetically displaceable armature piston with a piston rod, which, when a coil is energized, are displaced together in the direction of the suction valve and, when the coil is de-energized, eject liquid and carry out suction via the suction valve. The suction valve comprises a valve body which is accommodated in an axially nondisplaceable manner in a receptacle in a core flange, and which has a central bore through which liquid can pass from an antechamber into a guide sleeve guiding the piston rod. A disadvantage in this case is that, when the coil is energized, the end side of the piston rod strikes against the valve body and therefore noise is generated and vibration introduced into the pump. Another disadvantage is that, when the coil is de-energized, the liquid is guided exclusively via the central bore, and therefore a comparatively high negative pressure arises in the guide sleeve, and may form a counter force to the resetting movement of the armature piston.